Fire alarm switch



Dec. 29, 1953 w. NORMAND FIRE ALARM SWITCH Filed NOV. 9, 1951 M/fr/b Normand IN VEN TOR.

Mia WW 15? i atented Dec. 29, 1953 FIRE ALARM SWITCH Wilfrid N ormand',,.New Bedford, Mass.,. assignor to J oseph. W. Lajeunesse, New Bedford, Mass.

Application November 9, 1951, Serial'No. 255,633

2 Claims.

This invention relates to a fire alarm system and particularly to a fusible link controlling a circuit breaker for closing a circuit of a fire alarm system.

In fire alarm systems it is desirable to provide thermo-responsive switches at various places so that the elevated temperature due to the presence of a fire will produce a signal indicating the presence of a fire. It is desirable that such thermoresponsive switches be simple and inexpensive so that they may be er sily installed and of such low price that a large quantity of such switches may be utilized.

The present invention provides a thermally responsive switch having few and inexpensive parts.

The thermally responsive switch of the present invention includes an insulating panel having a pair of conducting posts mounted therethrough with me: us on the ends of the posts for connecting the end terminals of the wire circuits to the posts. A bridging member is provided in the form of a. spring wire biased to rrove in the closing position between the posts. The spring wire is retained in open position by means of a fusible link anchored onto the panel.

It is accordingly an object of this invention to provide an improved fire alarm system.

It is a further obiect of this invention to provide an improved thermo-responsive switch,

It is a further obiect of this invention to provide a thermo switch having a spring bis sed to closing position between a pair of contacts and a fusible link restraining the closing.

Other objects and many of the attendant advantages of the present invention will be obvious from the foregoing specification taken in conjunction with the accompanying drawings, in which:

Figure 1 is a perspective view of a circuit breaker according to the present invention;

Figure 2 is a similar view showing the back of the circuit breaker; and

Figure 3 is a diagrammatic illustration of a fire alarm system utilizing the circuit breaker of the present invention.

According to the exemple ry embodiment of the invention the fire alarm system includes a source of current iii which may well be the ordinary 110 volt system. A transformer i2 is connected to this source of supply and steps the voltage down according to the order of six volts so that the fire alarm is of universal nature and may be supplied either from the source of supply it: through the transformer E2 or an ordinary 6-volt battery may be utilized as a source of supply.

(Cl. ZOO-+142) The output terminals M and 16 of the transformer I2 are connected to the line wires l8 and 25 which provide a supply circuit for a signal device such as the bell 22.

Control switch for the circuit of the signal 22 includes the improved switch element of the present invention having a base 24 constructed of suitable insulating material and preferably having a plurality of apertures 26 and 28 for niounting the base on any suitable surface. An unstanding panel leg insulating member 38 is mounted on the base 24 and contact memhere in the form of a pair of posts 32 and 34 extending through the p: nel. The ends of the posts 32 and 34 extending through the panels are threaded and provided with a plurality of nuts or other suitable fasteners 39 and so that the wires l8 may be attached thereto. A contact bridging member is provided in the form of a spring do which is wound around one of the posts such as 34 and has an extremity 42 which is suitably anchored such as being placed against the base 24. The spring 48 is so tensioned that it tends to move into closed position between the posts 32 and .34 to provide a closed circuit between the terminal I4 and the bell 22. An anchor pin 46 is secured in the panel 30 and a fusible link 48 is provided between the anchor pin 46 and the end 50 of the spring 50. The fusible link is preferably designed to operate at a temperature of the order 165 degrees F.

Fusible link is preferably constructed with a substantially cylindrical body 52 having a pair of end members 54 and 56 including substantially cylindrical members slidable in the body 52 end secur d thereto by any suitable fusible material which are fusible at the desired order of temperature. The ends of the members 5 and are substantially flat and provided with apertures 58 and 60 secured to the end of the spring 52 and the anchor 46.

In the operation of the fire alarm system the circuit is energized by a suitable electrical source such as the battery or the transformer 12 and the switches are placed in any desired position about the premises. The spring 45 is brought to open position by means of a fusible link and in the event the temperature rises above the fusing point of the link the switches will close sounding the alarm and permitting extinguishing of the fire.

For the purposes of illustration I have shown and described a particular embodiment of the invention and described the same according to the best present understanding thereof, it will be apparent that many changes and be made therein without departing from the true spirit of the invention.

Having described the invention, what is claimed as new is:

1. A fire alarm switch comprising a base of insulating material, an upstanding panel of insulating material secured on said base, a pair of contact pins mounted on said panel, a conducting bridge, said bridge being biased to move into closing position between said contact pins, an anchor pin mounted on said panel, a link engaging said anchor pin and said bridge, said link restraining said bridge from moving to closing position, said link including a cylindrical member, a substantially tubular body slidably engaging said member, a fusible material of low melting point securing said body on said member.

2. In a fire alarm system, a thermally operated contactor comprising an insulating panel, a pair of spaced apart conducting posts extending 20 through said panel, one end of said posts being 4 threaded, threaded nuts mounted on said threaded ends for attaching circuit wires to said posts, a spring mounted on one of said posts, said spring being tensioned to move into contact with the other posts, a fusible link, said link having an aperture engaging said spring, an anchor on said panel, said link having a second aperture engaging said anchor, said link including a tubular body, a cylindrical end member slidably mounted in said body, a fusible material having a fusing temperature of the order of 165 joining said body and said end member.

WILFRID NORMAND.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 441,622 Shafier Nov. 25, 1890 478,788 Denio July 12, 1892 693,003 Gaschlin Feb. 11, 1902 

